Lubricating oil



' tants.

Patented Mar. 5, 1946 LUBRICATING OIL Bert H. Lincoln and Gordon D. Byrkit, Ponca City, Okla., assignors, by mesnc assignments, to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application August 2, 1941,

Serial No. 405.213

2 Claims.

Our invention relates to lubricating oils and more particularlyto improved lubricating oils of high film strength which are non-corrosive toward easily corroded bearing materials.

This is a continuation in part of our co-pending application, Serial No. 275,488, filed May 24, 1939, which issued as Patent No.. 2,257,750 October '7, 1941. v

In the development of new automotive and other types of engines, increased power and other requirements have led to the introduction of bearing metals, alloys, and mixtures which are readily attacked by oxidation products of the lubricant. Some of these newer bearing compositions are cadmium-silver, copper-lead and alloys of lead with alkali, and alkaline earth metals. These comparatively soft metals are corroded readily by oils which have been used for a short time in the engine. One method of overcoming this difficulty would be to use more resistant bearing compositions, and another would be to use an oil which does not develop these corrosive materials during use. Still another method would be to use a lubricant containing. a material which would react with and render inert the corrosive products as rapidly as they are formed. Our invention is not concerned with the first method but with the other two possibilities. Various addends have-been proposed to be addedto lubricants for the purpose of inhibiting the formation of corrosive materials during use. These may be called antioxidants, since they increase the time of use before rapid oxidation begins to occur and also decrease the rate of oxidation after it has started. -Va rious addends have also been proposed to be added to lubricants forthe purpose of reacting with such corrosive materials, as may in time be formed, and removing them from the oil so that they are unable to corrode the parts being lubricated. These'may be called precipi- The present invention proposed addends combining these two capabilities in the same molecule to give an unexpectedly superior activity in both respects over what would be predicted from a simply additive eifect.

One object of our invention is to provide a substantially non-corrosive lubricant for use with the.

newer, easily corroded bearing compositions. It is to be noted, however, that the improved lubricant here described is advantageously employed withall types of bearings, since it is less corrosive during use with any of the metals commonly encountered in practice.

Another object of the a lubricant inhibited against oxidation during use. A further object 'of our invention is to provide a lubricant containing an addend capable of reacting with or otherwise rendering inert such corrosive products as may be formed during extended use.

Other objects oi the invention will appear in the following description.

Our invention consists of the addition to lubricants of all kinds of salts or soaps of certain sulfur-bearing acids. These salts maybe of diverse types, and both the anionic and cationic parts ofthese soaps may be varied. Thus the cations may be purely organic ,or purely metallic, or organometallic. .In introducing sulfur into the acid radical of our salts, we have found that certain compounds rich in sulfur react with unsaturated acids to yield peculiarly effective addends for lubricating oils. By compounds rich in sulfur. we mean those containing more than per cent of sulfur in their molecular composition. Examples of these reagents are phosphorus pentasulfide, phos- Certain compounds are adsorbed or absorbed by metals forming tenacious films at the surface of metals which are able to stand high pressures. X-ray diffraction methodshave shown that comphorus trisulfide, and alkali metal polysulfides (sodium disulfide, potassium trisulflde, and higher sulfides'x' These particular sulfurizing agents yield particularly effectively bound sulfur in the molecule of the suliurized acid. The herein de-- scribed salts of such suliurized acids are extraordinary detergents and inhibitors of oxidation invention is to provide I when added to lubricants of all kinds. They contain no corrosive halogen and are more effective inhibitors than salts of acids containing sulfur in known structures such as sulfonic acids, sulfones, thicethers, heterocyclic sulfur, and the like.

In the following examples, any of the cations may be used with any of the anions to form these soaps, and it is to be understood that each of these combinations when blended, suspended, or otherwise mixed with a lubricant is an example of the invention.

I. Anions:

A. Alkali metal poiysulfide-treated acids:

1. Sodium pentasulflde-treated oleic acid Sodium tetrasulfide-treated linoleic acid Sodium trisulfide-treated linolenlc acid acid Potassium pentasulfide treated corn oil acids Potassium tri'sulfide-treate". soy

oil acids Potassiumtetrasulfide-treated lard .oil acids Lithium pentasulfide-treated tung oil acids .'Lithium tetrasulfide-treated abietic acid Lithium trisulfide-treated cholic acid Ammonium pentasulfide treated naphthenic acids B. Phosphorus sulfide treated acids (containing phosphorus and sulfur) 1. Phosphorus pentasulflde-treated corn oil acids Phosphorus trisulfide-treated corn oil acids I Phosphorus pentasulfide-treated soy 'oil acids Phosphorus pentasulfide-treated oleic acid Phosphorus pentasulflde-treated linoleic acid toco cnmmw II. Cations:

A. Metallic:

1. Group. 1Lithium, sodium, potassium, rubidium, cesium, copper.

2. Group 2-Calcium, strontium,

barium, beryllium, magnesium zinc, cadmium, mercury l 3. Group 3Aluminum, gallium; in-

dium, thallium 4. Group 4-Titanium, zirconium,

tin, lead 5. Group 5'Arsenic, antimony, bismuth' Sodium disulfide-treated elaidic we shall list them in accordance with their occurrence in the periodic table:

Group II:

Magnesium Zinc Cadmium Mercury Group III:

Boron Aluminum Thallium Group IV:

' Silicon Tin Lead Group V:

Arsenic Bismuth Antimony Group VI:

Tellurium Selenium Some of the organo-metallic radicals which may act as. cations informing the soaps to be used are:

Group II:

' Phenylniagnesium Propyl magnesium Methylzinc Cresylzinc Xylylcadmium Iso-amylcadmium Butylmercury Mesitylmercury Nitrophenylmercury Naphthylmercury Group In:

Phenylboron (II) Diphenylboron (I) o-Xylylboron (II) Dipropylaluminum Diethylthallium Diphenylthallium Di-p-tolylthallium Group IV:

6. Group 6-Chromium, molybde num, tungsten 7. Group 7 Manganese 8. Group 8Iron, cobalt, nickel B. Organo-metallic 1 These organo-metallic soaps may have, in the organo-metallic cation, an organic radical or radicals of the aliphatic or carbocyclic orheterocyclic series. The metallic element of the compound may be any one of a number of which the following are representative. For convenience,

The soaps derived from these organo-metallic radicals may contain in the organic radical or attached to the metal or in the anion of the soap an additional element or combination of elements including the halogens, sulfur, phosphorus, nitrogen, 01 oxygen.

Some of the combinations of the cations with a the anions are listed below, but it is obvious that all the possible combinations serve as examples of the invention when admixed with lubricating oils or greases:

1. Sodium salts of sulfurized corn oil acids 2. Aluminum salts of sulfurized beta. fat

. Stannous salts of sulfurized corn oil acids Stannic salts of sulfurized corn oil acids Ammonium salts of sulfurized soy oil acids Triphenyltin salts of sulfurized corn oil 'acids acids Phenylmagnesium salt of sulfurized oleic acid Nitrophenylmercuric salt of sulfurized lard oil acids Diphenylthallium salts of sulfurized soybean oil acids Triamylammonium salts of sulfurized lard oil acids Calcium salts of sulfurized corn oil acids Lead salts of sulfurized beta fat COO) JGbUlrP-CO While all of the above examples give the usual results described, we have found that particular emphasis should be placed on the organo-metallic salts of sulfur-bearing acids because they are especially effective antioxidants and corrosion inhibitors; furthermore the tin salts (metallic or organo-metallic) deserve notice as exhibiting these properties to a high degree.

The addends of this invention have a dual Diethylthallium salts of sulfurized corn oil- Barium salt of sulfurized oleic acid, sulfurized action in a lubricant. One action involves increased load-carrying ability and/or oiliness, while another action is directed to the stability of the lubricant. .Forload-carrying capacity, quantities ranging from 0.1 per cent to about 10.0 per cent must be added; As an anticorrosive agent and/or an an'tisludging agent, much smaller amounts must .be used, ranging from approximately 0.001 to 0.1 per cent. The action of the organo-metallic compounds is specific but diflicult to understand. These com--v pounds may be added to any type of hydrocarbon lubricants but show an unusual value in highly refined and solvent-treated lubricants.

The lubricating oil portion of the blends of our invention may be so-called mineral or hydrocarbon oils or may consist of wholly or contain only in part certain fatty oils including corn oil. soybean oil, lard oil, and the like. The blends may contain voltolized oils or synthetic oilsof lubricatinglviscosity. Soap-thickened or other-- wise thickened oils used'as greases may be employed. Addends for. other purposes such as pour point depressors may be present.

These compounds have varying degrees of' solubility in hydrocarbon oil. In some cases, it is necessary to use a solvent for the compound or to torm colloidal suspensions of the compound in oil.

The film strength and oxidation characteristics of solidand semisolid greases may be improved by the addition of small amounts of my. metallic soaps thereto. The chemical purity for use as extreme pressure addition agents is not critical. All that is important is that no corrosivecontaminants be present. Mixtures of a number of these compounds may be employed.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and I subcombinations. This is contemplated by and is within the scope of, our claims. It is further obvious that various changes may be made in details within the scope of our claims without f departing from the spirit of our invention. 40

It is therefore to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, we claim:

1. A lubricant comprising in combination a major'proportion-ofoil of lubricating viscosity and a minor proportion of a salt of a sulfurized relatively high molecular weight carboxylic acid, said carboxylic acid sulfurized by reaction.

with sodium trisulfide.

2. A lubricant comprising in combination a major proportion of oil lubricating viscosity and a minor proportion of the calcium salt of sulfurized oleic acid, said oleic. acid sulfurized by reactionwith sodium'trisulfide.

' BERT H. LINCOLN.

GORDON D. BYRKIT. 

